DESCRIPTION: (Applicant's Abstract) Cocaine abuse among women of reproductive age has become increasingly evident. The acute and chronic effects of cocaine are more pronounced in the female than the male rat and evidence suggests that these gender differences are hormonally, not developmentally, based. Behavioral, neurochemical, endocrinological and molecular biological tools will be used to determine the role of the ovarian steroid hormones, estrogen (E), and progesterone (P), in the response to cocaine in the female rat. Antisense oligonucleotides for specific steroid hormone receptors will be used to deplete E or P receptors and determine if the behavioral response to a subsequent cocaine treatment paradigm (either acute or chronic) is altered.